Table 3.
Effects of the variable-number tandem repeat polymorphism in the dopamine receptor D4 gene on the maximal response to 125 mg MDMA (mean ± SD (N) and statistics) corrected with MDMA AUC6 (exclusive plasma concentrations).
| DRD4 VNTR | ≤8 Repeats | >8 Repeats | F | p value | p valuea | η2 |
|---|---|---|---|---|---|---|
| N | 87 | 59 | ||||
| Female, N [%] | 44 [51] | 31 [53] | ||||
| Drug experience, N [%] | 31 [36] | 22 [37] | ||||
| MDMA plasma concentration Cmax, ng/ml | 229 ± 44 (87) | 226 ± 55 (59) | 0.16 | NS | NS | 0.001 |
| MDMA plasma concentration AUC6, ng*h/ml | 965 ± 189 (87) | 948 ± 221 (59) | 0.25 | NS | NS | 0.002 |
| Visual Analog Scale rating ΔEmax | ||||||
| Any drug effect | 74 ± 26 (87) | 71 ± 26 (59) | 0.35 | NS | NS | 0.002 |
| Good drug effect | 73 ± 30 (87) | 73 ± 26 (59) | 0.01 | NS | NS | 0.000 |
| Bad drug effect | 17 ± 23 (87) | 15 ± 27 (59) | 0.08 | NS | NS | 0.001 |
| Drug liking | 74 ± 31 (87) | 75 ± 25 (59) | 0.12 | NS | NS | 0.001 |
| Stimulated | 63 ± 35 (87) | 63 ± 34 (59) | 0.07 | NS | NS | 0.000 |
| High mood | 68 ± 34 (87) | 71 ± 31 (59) | 0.51 | NS | NS | 0.003 |
| Concentration | 8.2 ± 17 (87) | 9.0 ± 15 (59) | 0.09 | NS | NS | 0.001 |
| Talkative | 20 ± 19 (87) | 23 ± 19 (59) | 1.27 | NS | NS | 0.008 |
| Appetite | -5.8 ± 33 (47) | -10 ± 26 (25) | 0.41 | NS | NS | 0.006 |
| Tired | 24 ± 32 (68) | 13 ± 32 (41) | 2.63 | NS | NS | 0.023 |
| Fear | 6.6 ± 18 (56) | 5.6 ± 14 (38) | 0.08 | NS | NS | 0.001 |
| Happy | 26 ± 20 (59) | 30 ± 17 (44) | 1.33 | NS | NS | 0.012 |
| Want to be hugged | 13 ± 19 (40) | 13 ± 18 (34) | 0.01 | NS | NS | 0.000 |
| Want to hug | 14 ± 19 (40) | 13 ± 17 (34) | 0.02 | NS | NS | 0.000 |
| Vital signs parameters ΔEmax | ||||||
| Systolic blood pressure, mmHg | 25 ± 12 (87) | 22 ± 13 (59) | 1.24 | NS | NS | 0.008 |
| Diastolic blood pressure, mmHg | 14 ± 9 (87) | 13 ± 10 (59) | 0.11 | NS | NS | 0.001 |
| Mean arterial pressure, mmHg | 17 ± 9 (87) | 17 ± 10 (59) | 0.11 | NS | NS | 0.001 |
| Heat rate beat/min | 18 ± 15 (87) | 17 ± 14 (59) | 0.03 | NS | NS | 0.000 |
| Rate pressure product, mmHg/min | 4,561 ± 2,967 (87) | 4,393 ± 2,746 (59) | 0.06 | NS | NS | 0.000 |
| Body temperature, °C | 0.3 ± 0.5 (87) | 0.2 ± 0.5 (59) | 0.19 | NS | NS | 0.001 |
| Adjective Mood Rating Scale rating ΔEmax | ||||||
| Activity | 2.3 ± 5.2 (87) | 2.7 ± 4.9 (59) | 0.26 | NS | NS | 0.002 |
| High mood | 2.8 ± 3.3 (87) | 3.0 ± 3.0 (59) | 0.18 | NS | NS | 0.001 |
| Fear/depression | 1.1 ± 3.7 (87) | 0.9 ± 3 (59) | 0.10 | NS | NS | 0.001 |
N, number of subjects; SD, standard deviation; NS, not significant; Δ, values are change scores from placebo; ap value additionally corrected for multiple comparisons according to the Nyholt method; η2, eta square.